In the pilot, Imogene Coca's character was called "Shagg." When the producers were made aware of the fact that "shag" is a slang vulgarism in the U.K., they changed her name to "Shadd" - but didn't fix the pilot, which aired (as the premiere episode) as originally filmed.
Halfway through the one-season run, the plot was reversed in an attempt to bolster the show's ratings, which were not as spectacular as CBS had hoped they would be. The two astronauts, who had traveled back in time, now found a way to return to 1966 and took the stone-age family with them - so the rest of the run played out with Gronk, Shadd, et al trying to adjust to life in 1966-era NYC.
Although the show only lasted one season and was not ranked high in the Nielson ratings, it was immortalized when Isaac Asimov referred to it in an essay he wrote in February 1967 titled, "Impossible, That's All" (about how it was impossible for anything to go faster than light). The essay was later included as a chapter of Asimov's book, "Science, Numbers and I".